The SSI accelerating modules are recommended for use in DC motor circuits and are used to control the closure of the accelerating contactors. They are frequently used on DC crane control and mill auxiliary control panels.

The Static Frequency Sensitive (SZF) relays are recommended for use in AC wound rotor motor circuits to monitor motor frequency and operate an output relay at a specific programmed frequency. They are used on AC crane control panels.

They are designed to have a low resistance and impedance relative to most motor and load circuits such that they can be placed in series with loads without noticeably dropping the load voltage, or affecting load current. (See catalog applications below 1.5HP)